6420871 has 4 divisors (see below), whose sum is σ = 6433672. Its totient is φ = 6408072.

The previous prime is 6420853. The next prime is 6420877. The reversal of 6420871 is 1780246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6420871 - 2¹⁷ = 6289799 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6420877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5616 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (1608418).

Almost surely, 2^6420871 is an apocalyptic number.

6420871 is a deficient number, since it is larger than the sum of its proper divisors (12801).

6420871 is a wasteful number, since it uses less digits than its factorization.

6420871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12800.

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 6420871 is about 2533.9437641747. The cubic root of 6420871 is about 185.8651564387.

The spelling of 6420871 in words is "six million, four hundred twenty thousand, eight hundred seventy-one".